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Shiro, Ayumi*; Shobu, Takahisa; Okada, Tatsuya*
Zairyo, 71(4), p.354 - 360, 2022/04
Recrystallization process of an aluminum (Al) single crystal was observed in situ using synchrotron X-rays. Al single-crystalline samples were deformed in tension along a 111 direction to a strain of 8%, and were subsequently annealed at 753 K. The changes in the shape and intensity of diffraction spots were analyzed using a two-dimensional detector. A diffraction spot from the deformation matrix had three peaks which reflected a sub-grained microstructure of the sample. The observation during annealing unveiled the appearance of diffraction spots from a recrystallized grain at 330.8 s. As the diffraction spots from the recrystallized grain became larger, the diffraction spots from the deformation matrix gradually disappeared. The application of the X-ray topography method revealed the crystal orientation variation in a recrystallized grain in order of 0.001 degree.
Kitagaki, Toru
Journal of Nuclear Materials, 557, p.153254_1 - 153254_8, 2021/12
Times Cited Count:1 Percentile:15.7(Materials Science, Multidisciplinary)Shiro, Ayumi*; Okada, Tatsuya*; Shobu, Takahisa
Mechanical Engineering Journal (Internet), 8(6), p.21-00106_1 - 21-00106_8, 2021/12
The objective of the present study was to carry out observations of deformation and annealing processes of aluminum single crystals using a synchrotron radiation X-rays at SPring-8. Al single-crystalline samples having a 111 orientation parallel to the longitudinal direction were grown by a Bridgman method. The samples were deformed in tension to a nominal strain of 0.08 at room temperature using an in-line tensioning apparatus. Post-deformation annealing at 480 C was subsequently carried out in the same apparatus. A two-dimensional detector was used to detect multiple diffracted beams from the sample during the deformation and annealing processes. The volume irradiated by the X-ray beam was found to be composed of three regions having a small orientation difference, which was attributable to sub-grained microstructures of the sample. Detailed analyses of a diffraction spot intensity showed that the sub-grained microstructures were surpassed by dislocated microstructures with the increase in the tensile strain. During the post-deformation annealing, diffraction spots from a recrystallized grain first appeared at 180 s after the temperature reached 480 C. Coexistence of diffraction spots from the deformation matrix and recrystallized grain lasted only for about 22 s in the irradiated volume. The migration rate of the boundary between the deformation matrix and recrystallized grain was estimated to be of the order of several micrometers/s.
Shobu, Takahisa; Shiro, Ayumi*; Kono, Fumiaki*; Muramatsu, Toshiharu; Yamada, Tomonori; Naganuma, Masayuki; Ozawa, Takayuki
Quantum Beam Science (Internet), 5(2), p.17_1 - 17_9, 2021/06
The automotive industries employ laser beam welding because it realizes a high energy density without generating irradiation marks on the opposite side of the irradiated surface. Typical measurement techniques such as strain gauges and tube X-rays cannot assess the localized strain at a joint weld. Herein high-energy synchrotron radiation X-ray diffraction was used to study the internal strain distribution of laser lap joint PNC-FMS steels (2- and 5-mm thick) under loading at a high temperature. As the tensile load increased, the local tensile and compressive strains increased near the interface. These changes agreed well with the finite element analysis results. However, it is essential to complementarily utilize internal defect observations by X-ray transmission imaging because the results depend on the defects generated by laser processing.
Lam, T.-N.*; Tsai, C.-W.*; Chen, B.-K.*; Lai, B.-H.*; Liu, H.-C*; Kawasaki, Takuro; Harjo, S.; Lin, B.-H.*; Huang, E.-W.*
Metallurgical and Materials Transactions A, 51(10), p.5023 - 5028, 2020/10
Times Cited Count:12 Percentile:61.56(Materials Science, Multidisciplinary)Tomota, Yo*; Wang, Y.*; Omura, Takahito*; Sekido, Nobuaki*; Harjo, S.; Kawasaki, Takuro; Gong, W.*; Taniyama, Akira*
Tetsu To Hagane, 106(5), p.262 - 271, 2020/05
Times Cited Count:0 Percentile:0(Metallurgy & Metallurgical Engineering)Morooka, Satoshi
Hozengaku, 19(1), p.29 - 34, 2020/04
no abstracts in English
Kusano, Shogo*; Matsumura, Daiju; Ishii, Kenji*; Tanaka, Hirohisa*; Mizuki, Junichiro*
Nanomaterials (Internet), 9(4), p.642_1 - 642_14, 2019/04
Times Cited Count:7 Percentile:36.99(Chemistry, Multidisciplinary)Harjo, S.; Tsuchida, Noriyuki*; Abe, Jun*; Gong, W.*
Scientific Reports (Internet), 7(1), p.15149_1 - 15149_11, 2017/11
Times Cited Count:103 Percentile:94(Multidisciplinary Sciences)Tsuchida, Noriyuki*; Nagahisa, N.*; Harjo, S.
Materials Science & Engineering A, 700, p.631 - 636, 2017/07
Times Cited Count:9 Percentile:41.54(Nanoscience & Nanotechnology)Tomota, Yo*; Gong, W.*; Harjo, S.; Shinozaki, Tomoya*
Scripta Materialia, 133, p.79 - 82, 2017/05
Times Cited Count:25 Percentile:73.68(Nanoscience & Nanotechnology)Morooka, Satoshi; Kanata, Hiroyuki*; Oba, Yojiro*; Sato, Masugu*
Heisei-28-Nendo SPring-8 Sangyo Shinbunya Shien Kadai, Ippan Kadai (Sangyo Bunya) Jisshi Hokokusho, p.95 - 98, 2017/00
no abstracts in English
Tsuji, Akihiro*; Zhang, S.*; Hashimoto, Tadafumi*; Okano, Shigetaka*; Shobu, Takahisa; Mochizuki, Masahito*
Zairyo, 65(9), p.665 - 671, 2016/09
It is necessary to control weld residual stress which has negative influence on fracture strengths. In structural steel welds, complex residual stress fields are formed due to phase transformation that occur according to the thermal cycles. In this study, in-situ evaluation of phase transformation and transitional stress simultaneously during welding is discussed. In the test using SM490A, after cooling process, stress evaluated by this system showed good agreement with that evaluated by lab X-ray. During austenite to ferrite transformation in weld metal, tensile stress occurred in austenite and compressive stress occurred in ferrite. Moreover, stress concentration was occurred in ferrite phase immediately after the start of phase transformation. Also, stress concentration was occurred in austenite phase just before the end of phase transformation.
Matsumura, Daiju; Okajima, Yuka*; Nishihata, Yasuo
Journal of Physics; Conference Series, 712(1), p.012042_1 - 012042_4, 2016/06
Times Cited Count:0 Percentile:0.03(Physics, Applied)Takahashi, Masamitsu; Yoneda, Yasuhiro; Yamamoto, Naomasa*; Mizuki, Junichiro
Physical Review B, 68(8), p.085321_1 - 085321_5, 2003/08
Times Cited Count:17 Percentile:62.72(Materials Science, Multidisciplinary)The , and phases of the GaAs(001)-24 surface have been investigated by surface X-ray diffraction in an As flux and at temperatures ranging from 480C to 610C. It has been found that the fractional-order peaks originating from the fourfold symmetry show shift in the [110] direction as well as significant broadening of the peaks in the and phases. The direction of the peak shift is characteristic in each phase. This behavior is explained by the formation of the antiphase domain boundaries. The atomic structure of the domain boundaries is discussed.
Kakuta, Tsunemi; Shikama, Tatsuo*; *; ; Shamoto, Naoki*; *
Proc. of Int. Conf. on Optical Technology and Image Processing in Fluid,Thermal and Combustion Flow, p.1 - 5, 1998/00
no abstracts in English
Ono, Hideo
Nihon Genshiryoku Gakkai-Shi, 32(11), p.1099 - 1100, 1990/11
no abstracts in English
Shobu, Takahisa; Shiro, Ayumi; Muramatsu, Toshiharu; Yamada, Tomonori; Naganuma, Masayuki; Ozawa, Takayuki
no journal, ,
no abstracts in English
Shobu, Takahisa; Shiro, Ayumi; Muramatsu, Toshiharu; Yamada, Tomonori; Naganuma, Masayuki; Ozawa, Takayuki
no journal, ,
no abstracts in English
Shobu, Takahisa
no journal, ,
no abstracts in English